For testing purposes I modded in 3 radioman on my gato. It doesnt seem to work for the Allied side - or rather, it actually seems to work in reverse.
Not only did I never get a radio call about shipping, I had alot more planes buzzing round me than normal. Now I run the ASW mod to cut down on planes, and it was almost as bad as stock with these guys! I sank one ship, moved well over 800 miles over the space of days, submerged whenever a plane showed on the SD and was never spotted - yet the buggers continue to fly over me.
Anyone else see such negative behavior when playing as a US sub? If so, it may be something that can be corrected via mod.